Mathematical Olympiad - practice for 13 year olds
Number of problems found: 66
- Quadrilateral 82616
Triangle ABC is divided into line segments. Lines DE and AB are parallel. Triangles CDH, CHI, CIE, and FIH have the same area, namely 8 dm². Find the content of quadrilateral AFHD. - Two-digit 82521
Karel had to multiply two two-digit numbers. Out of care, he changed the order of the digits in one of the factors and got a product that was 4,248 less than the correct result. What is the correct result? How much should Karl have earned? - Quadrilateral calc
The square ABCD is given. The midpoint of AB is E, the midpoint of BC is F, CD is G, and the midpoint of DA is H. Join AF, BG, CH, and DE. Inside the square (approximately in the middle), the intersections of these line segments form a quadrilateral. Calc - Respectively 81293
The figure shows the squares ABCD, EFCA, CHCE, and IJHE. Points S, B, F, and G are, respectively, the centers of these squares. Line segment AC is 1 cm long. Determine the area of triangle IJS. Please help...
- Three-digit 80768
Nikola had one three-digit and one two-digit number written in her notebook. Each of these numbers was made up of different digits. The difference in Nicole's numbers was 976. What was their sum? - Grandchildren 80639
The average age of the grandfather, grandmother, and their five grandchildren is 26 years. The average age of the grandchildren themselves is 7 years. Grandma is a year younger than grandpa. How old is grandma? - Different 64304
If the boys let the two girls in front of them, how many different ways can Anka, Betka, Cyril, Daniel, and Erik line up in the dining room? - Two-digit 64294
How many natural two-digit numbers can we form from the digits 0, 1, 2, and 3 if the numerals cannot be repeated in these numbers? - Grandfather 63074
My only son was born when I was 37 years old. That was exactly 32 years after the death of my grandfather, and he died at the age of 64. Dedecek was 12 years older than Grandma; they got married in 1947, just when Grandma was 18 years old. What year was m
- Three-digit unknown int
Viera compiled different three-digit numbers from three given digits. When she added up all these numbers, she published 1221. What numbers did Vierka use? Identify five options - Below-average 60271
In a given group of numbers, one number is equal to the average of all, the largest number is 7 larger than the average, the smallest is 7 smaller than the average, and most numbers in the group have below-average values. What is the smallest number of nu - MO Z7–I–6 2021
In triangle ABC, point D lies on the AC side and point E on the BC side. The sizes of the angles ABD, BAE, CAE, and CBD are 30°, 60°, 20°, and 30°, respectively. Find the size of the AED angle. - Two ports
Between the ports of Mumraj and Zmatek, two ships commute along the same route. They spend negligible time in ports, turn around immediately, and continue sailing. At the same time, a blue ship departs from the port of Mumraj, and a green ship departs fro - Coloured numbers
Mussel wrote four different natural numbers with colored markers: red, blue, green, and yellow. When the red number divides by blue, it gets the green number as an incomplete proportion, and yellow represents the remainder after this division. When it div
- Squirrels
The squirrels discovered a bush with hazelnuts. The first squirrel plucked one nut, the second squirrel two nuts, and the third squirrel three nuts. Each new squirrel always tore one nut more than the previous squirrel. When they plucked all the nuts from - All pairs
Find all pairs (m, n) of natural numbers for which is true: m s (n) = n s (m) = 70, where s(a) denotes the digit sum of the natural number a. - Dance ensembles
Four dance ensembles were dancing at the festival. None had less than ten and more than 20 members. All dancers from some of the two ensembles were represented in each dance. First, 31 participants were on the stage, then 32, 34, 35, 37, and 38. How many - Construct 11511
Construct the diamond ABCD so that its diagonal BD is 8 cm and the distance of apex B from the line AD is 5 cm. Specify all options - Subtract 10001
For five whole numbers, if we add one to the first, multiply the second by the second, subtract three from the third, multiply the fourth by four, and divide the fifth by five, we get the same result each time. Find all five of the numbers that add up to
Do you have homework that you need help solving? Ask a question, and we will try to solve it.